Thu Jan 13, 2011 1:01 pm
This is usually done by bringing the bottle to 25 °C, shaking it vigorously and then piercing the cap with a needle connected to a pressure gauge. The pressure is noted and the gas is then allowed to bleed into a sodium hydroxide solution contained in a special buret. Any gas which doesn't dissolve is air and the volume of this air us used to correct the pressure reading which is then entered into the ASBC table (the one we all use to find how many volumes of dissolved CO2 correspond to CO2 gauge pressure). The apparatus is made by Zahm and Nagel and is, I assume, reasonably expensive. There is another ASBC method involving a syringe but it is supposedly limited to 1.6 vols and I see problems with it. Then there are high dollar solutions (Anton Paar has an instrument).